1. Field of the Invention
Artificial and synthetic DNA sequences have gained extensive use with development of the field of synthetic biology in the past decade. The present invention relates to use of artificial nucleotide sequences in the field of bioluminescence, which is emission of light by living organisms. Bioluminescence of bacterial organisms is mediated by the bacterial LUX operon. The LUX operon encodes for the bacterial luciferase, the light emitting enzyme, as well as enzymes responsible for synthesis of luciferins, substrates required for the light emission reaction. The operon contains genes named C-D-A-B-E(-G), where Lux A and Lux B code for the components of the luciferase and Lux C, D and E code for a fatty acid reductase complex producing an aldehyde necessary for the reaction. LuxG codes for an enzyme thought to participate in the turnover of the second luciferin, the flavin mononucleotide.
2. Description of Related Art
In biotechnology, genes of the LUX operon have a wide range of applications. For instance, the LUX operon is utilized as a reporter in a variety of bacterial and plant biosensors. Bacterial cells of naturally non-glowing species such as E. coli have been engineered to contain the LUX operon inducible by pre-determined classes of chemicals. These cells start glowing in the presence of these specific compounds, reporting on the composition or toxicity of the sample. Plants engineered with a fully functional LUX operon have been contemplated for use as phytosensors, monitoring the conditions of the plant and the environment. Furthermore, ornamental plants have been engineered to contain a LUX operon to produce novel and unique types of glowing ornamental plants. The U.S. ornamentals market was sized at approximately $21B in the early 2000's, and the entire worldwide market for ornamental plants has been estimated to be over $100B.
The ornamental plant market is driven by innovation, where outdated varieties are inevitably replaced by new types of plants and flowers. New colors of roses and carnations, and new shapes and colors of petunias, find their way to the marketplace every year. Generation of new and esthetically pleasing varieties is known to be the key force driving the floriculture industry and stimulating its growth.
However, one of the major limitations of the applicability of LUX operon-based technologies, particularly in plants, is low levels of light emission in plants expressing LUX genes. Therefore means to engineer the LUX operon to enhance and augment plant light emission are needed.
The present invention addresses this problem, and provides several means of enhancing light emission, instrumental in producing new, exciting varieties of highly autoluminescent ornamental plants, as well as additional plant products, such as more effective autoluminescent plant phytosensors.